Lubricating oil



Patented Get. 7, 1941 LUBRICATING OIL Bert H. Lincoln and Gordon D. .Byrkit, Ponca City, Okla., assignors to Continental Oil Company, Ponca City, Okla., a corporation of Dela- No Drawing.

Application July 5, 1940,

Serial No. 344,112

3 Claims.

Our invention relates to lubricating oils and more particularly to an improved lubricating oil of high film strength which is noncorrosive toward easily corroded bearing materials.

This application is a continuation-in-part of our co-pending application, Serial No. 275,488, filed May 24, 1939.

In the development of new automotive and other types of engines, increased power and other requirements have led to the introduction of bearing metals, alloys and mixtures which are readily attacked by oxidation products of the lubricant. Some of these newer bearing compositions are cadmium-silver, copper-lead and alloys of lead with alkali and alkaline earth metals. corroded readily by oils which have been used for a short time in the engine. One method of overcoming this difliculty would be to use more resistant bearing compositions, and another would be to use an oil which does not develop these corrosive materials during use. Still another method would be to use a lubricant containing a material which would react with and render inert the corrosive products as rapidly as they are formed.

Our invention is not concerned with the first method but with the other two possibilities. Various addends have been proposed for addition to lubricants for the purpose of inhibiting the formation of corrosive materials during use. These may be called antioxidants, since they increase the time of use before rapid oxidation begins and decrease the rate of oxidation after it has started. Various addends have also been proposed to be added to lubricants for the purpose of reacting with such corrosive materials, as may in time be formed, and removing them from the oil so that they are unable to corrode the parts being lubricated. These may be called precipitants.

The present invention proposes addends combining these two capabilities in the same molecule to give an unexpectedly superior activity in both respects over hat would. be expected from simply the additi e effect alone.

Certain compounds are adsorbed or absorbed by metals forming tenacious films at the surface of metals which are able to stand high pressures.

X-ray diffraction methods have shown that compounds containing highly polar molecules, that is, molecules of unsymmetrical character containing an atom or ground atoms exhibiting a secondary or residual valence, tend to produce regimentation of the molecules of hydrocarbon oil when added thereto. A metal immersed in a These comparatively soft metals are strongly polar compound will show a film of the compound in which there is a regimentation of molecules oriented with respect to the surface of the metal by which they are adsorbed or absorbed.

One object of our invention is to provide a substantially noncorrosive lubricant for use with the newer, easily corroded bearing compositions. It is to be noted, however, that the improved lubricant here described is advantageously employed with all types of bearings, since it is less corrosive during use with any of the metals commonly encountered in practice.

Another object of the invention is to provide a lubricant inhibited against oxidation during use.

A further object is to provide a lubricant containing an addend capable of reacting with or otherwise rendering inert such corrosive products as may be formed during extended use.

Other objects of the invention will appear in the following description.

Our invention comprises the addition to all kinds of lubricants of stannous and stannic salts or soaps of sulphur bearing carboxylic (including thiocarboxylic) acids. The anions of these soaps are susceptible to many variations. They may be thio-ethers, mercaptans, sulfones, heterocyclic sulphur rings, or sulphurized unsaturated acids or sulphur chloride treated unsaturated acids and the like. Both the stannous and stannic soaps of each of the following acids when blended, suspended or otherwise mixed with a lubricant is an example of our invention.

A. Sulphurized acids roooqazoipgorcu 4. Phosphorus pentasulflde treated oleic acid 5. Phosphorus pentasulflde treated linoleic acid C. Sulphur chloride treated acids 1. Sulphur chloride treated oleic acid 2. Sulphur chloride treated linoleic acid 3. Sulphur chloride treated linolenic acids 4. Sulphur chloride treated elaidic acid 5. Sulphur chloride treated corn oil acids 6. Sulphur chloride treated soy oil acids '7. Sulphur chloride treated lard oil acids 8. Sulphur chloride treated tung oil acids 9. Sulphur chloride treated abietic acid '10. Sulphur chloride treated cholic acid Sulphur chloride treated naphthenlc acids D. Sulphur-bearing acids of known constitution 1. Mercapto acids a. Mercapto-stearic acid b. Mereapto-acetic acid c. 'Ihiophenol--carboxylic acid d. 'I'hiophenylacetic acid e. Mercapto-chlorostearic acid Sulfldo acids (1. Methylmercapto-stearic acid b. Ethylmercaptophenyl acetic acid c. Amylmercaptobenzene-4 carboxylic acid. d. Methylmercapto-chlorostearic acid 3. SulIone acids a. Ethylsulfone-beta-carboxylic acid b. Phenylsulfone-i-carboxylic acid 0. Chlorophenylsulfone 2 carboxylic acid 4. Disulfldo acids a. Ethyldisulfldobenzene 2 carboxylic acid b. Amyldisulfldophenylacetic acid 0. Benzyldisulfidobenzylstearic acid 5. Sulfato acids 0. Acid sulfate of 12-hydroxystearic acid b. Acid sulfate of ricinoleic acid 0. Neutral sulfate 01 12-hydroxystearlc acid Sulfito acids a. Sulfite oi 12-hydroxystearic acid b. Sulfite of ricinoleic acid Thiocarboxylic acids a. Ethylxanthate b. Butylxanthate c. Amylxanthate d. Benzylxanthate e. Thiolstearic acid, CuHasCOSH f. Thionstearic acid, C17H35CSOH g. Dithiostearic acid, CnHasCSSH Some of the tin soaps of these anions are listed below, but it is to be understood that any stannous or stannic soap oi. the above anions serve as examples of the invention when admixed with lubricating oils or greases:

1. Stannous salts of sulphurized corn oil acids 2. Stannic salts of sulphurized corn oil acids Stannous salts or sulphurized beta tat Stannic salts of sulphurized beta fat MID .Stannous salt of sulphur chloride treated 9. Stannous salt of sulphurized soy bean oil acids 10. Stannic salts of sulphurized soy bean acids 11. Stannous salts of methylmercaptostearic acid 12. Stannic salt of methylmercaptostearic acid 13. Stannous salt of ethylsulfone-beta-carboxylic acid 14. Stannic salt of ethylsulione-beta-carboxylic acid 15. Stannous salts of sulphur chloride treated corn oil acid 16. Stannic salts of surphur chloride trea corn oil acid 17. Stannous salts or sulphur chloride treated soy bean oil acids 18. Stannic salts of sulphur chloride treated soy bean oil acids 19. Stannous salts of sulphur chloride treated beta fat 20. Stannic salts of sulphur chloride treated beta fat 21. Stannous salt of sulphurized linoleic acid 22. Stannic salt of sulphurized linoleic acid 23. Stannous salt of sulphurized oleic acid 24. Stannic salt 01' sulphurized oleic acid 25. Stannous salts of sulphurized lard oil acids 26. Stannic salts of surphurized lard oil acids 27. Stannous salts of surphur chloride treated lard oil acids Stannic salts of sulphur chloride treated lard oil acids Stannous salt of amyldisulfldo-phenylacetate Stannic salt of amyldisulfido-phenylacetate Stannous mercaptostearate Stannic mercaptostearate Stannous phenylsulfone-4-carboxylate Stannic phenylsulfone-4-carboxylate Stannous amylxanthate Stannic amylxanthate Stannous salt of the reaction product of benzyldisulfide, dichlorostearic acid and aluminum chloride Stannic salt of the reaction product 0! benzyldisulfide, dichlorostearic acid and aluminum chloride Stannous salt or dixanthylstearic acid methyl ester Stannic salt of dixanthylstearic acid methyl ester Stannous salts of phosphorus pentasulfide treated corn oil acids Stannic salts of phosphorus pentasulflde treated corn oil acids These stannous and stannic salts possess the anti-oxidant and corrosion inhibiting properties to a high degree.

The addends of this invention have a dual action in a lubricant. One action involves increased load-carrying ability and/or oiliness, while another action is directed to the stability of the lubricant. For load-carrying capacity, quantities ranging from 0.1 per cent to about 10.0 per cent must be added. As an anticorrosive agent and/or an antisludging agent, much smaller amounts must be used, ranging from approximately 0.001 to 0.1 per cent. The action of these sulphur-bearing tin soaps is specific but v(iiiilcult to understand. These compounds may be added to any type of hydrocarbon lubricants, but show an unusual value in highly refined and solvent-treated lubricants.

The lubricating oil portion of the blends of our invention may be so-called mineral or hydrocarbon oils or may consist of wholly or contain only in part certain fatty oils including corn oil, soy bean oil, lard oil, and the like. The blends may contain volatilized oils or synthetic ofls of lubricating viscosity. Soap thickened or otherwise thickened-oils used as greases may be employed. Addends for other purposes such as pour point depressors may be prsent.

These compounds have varying degrees of solubility in hydrocarbon oil. In some cases, it is necessary to use a solvent for the compound or to form colloidal suspensions of the compound in oil.

The film strength and oxidation characteristics of solid and semisolid greases may be improved by the addition of small amounts oi our sulphur-bearing tin soaps thereto. The chem- "ical purity for use as extreme pressure addition agents is not critical. All that is important is that no corrosive contaminants be present. Mixtures of a number of these compounds may be employed.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and nib-combinations. This is contemplated by and is within the scope of our claims. It is iurther obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is therefore to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, we claim:

1. A lubricant comprising in combination a major proportion of an oil of lubricating viscosity and a minor proportion of a tin salt of a sulphurized carboxylic acid, said carboxylic acid sulphurized by treatment with sulphur chloride.

2. A lubricant comprising in combination a major proportion of an oil of lubricating viscosity and a minor proportion of a tin salt of a sulphurized aliphatic carboxylic acid, said aliphatic carboxylic acid sulphurized with sulphur chloride.

3. A lubricant comprising in combination a major proportion of an oil of lubricating viscosity and a minor proportion 01 stannic salts of sulphurized soy bean oil acids. said soy bean oil acids sulphurized by treatment with sulphur chloride.

BERT H. LINCOLN. GORDON D. BYRKIT. 

